The invention relates to a brake wear sensor of a disc brake, as well as to a method for associating a measurement signal of a brake wear sensor of this type.
Disc brakes of different designs are known and are often fitted with a sensor for determining wear of the brake pads and the brake disc. In one embodiment, a brake wear sensor of this kind has a potentiometer, which can be adjusted by means of a planetary mechanism. In this case, the planetary mechanism is coupled to an adjustment device, the adjustment travel of which is transmitted as a rotation angle to the planetary mechanism. The potentiometer can already be provided with an integrated electronic system for conditioning measurement signals.
Such brake wear sensors have proven very successful. Given the constantly growing automation and monitoring of brakes and braking processes, there is a requirement to detect additional characteristic variables. One such variable is the stroke of a pivoted braking lever of such a disc brake, for example. However, an additional sensor which requires a corresponding installation space and associated installation costs, including the outlay on components, is required to sense each additional characteristic variable.
It is therefore an object of the present invention to provide an improved brake wear sensor.
This and other objects are achieved by a brake wear sensor, and an associated operating method, designed so that the brake wear sensor detects at least two different input or characteristic variables.
Accordingly, a brake wear sensor of a disc brake has the following: a sensor unit; a mechanism interacting with the sensor unit; and a central drive element, which is in engagement with the mechanism, for an input or characteristic variable associated with brake wear, wherein the brake wear sensor has at least one additional input for a further input or characteristic variable.
By means of this additional input on a brake wear sensor, it is possible, on the one hand, to use most existing components. Moreover, this means that no further sensor involving expensive electronics is necessary to detect an additional characteristic variable or, indeed, a plurality of variables.
The at least one additional measurement signal can be produced merely by modifying the arrangement of the existing components in the sensor and by adding a further drive option to the existing mechanism.
In this arrangement, the existing mechanism is expanded by the at least one additional input, thereby obtaining the additional ability for adjustment by way of the additional input. Only a few modifications or additions are required for this purpose, and these do not significantly increase the existing installation space. There is no need for an additional sensor for the additional characteristic variable.
In one embodiment, the at least one additional input is in interaction with the mechanism via an additional drive mechanism. In a simple embodiment, this can be a spur wheel mechanism, wherein an additional drive element has the spur wheel, which is in engagement with toothing or additional toothing on a gearwheel. A worm gear mechanism, a bevel wheel mechanism, a coupling rod, a tappet or a cam mechanism are also possible for this purpose, either individually or in combination with appropriate corresponding mating parts on the mechanism. It is expedient for the sensor to be pressed against a stop by the force of a return spring in the rest position.
In a preferred embodiment, the mechanism of the brake wear sensor, which interacts with the sensor unit, is a planetary mechanism. It is a simple matter here, for example, to provide a planet carrier wheel with a drive section which forms part of the additional drive mechanism. The drive section can be formed by external toothing or internal toothing, for example.
The sensor unit can be a potentiometer; of course, it can also be an electronic device for processing and conditioning or evaluating measurement signals.
The sensor unit can also have an inductive and/or capacitive pick-up, either alone or in combination with other pick-ups. In this case, an electronic device in the sensor unit can adapt, e.g. digitize, the measurement signals in an appropriate manner for further processing, for example. Moreover, inductive and capacitive pick-ups offer the advantage of contactless and, hence, frictionless actuation and are furthermore maintenance-free.
A method for associating a measurement signal of a brake wear sensor of a disc brake with one of at least two different input or characteristic variables of the brake wear sensor is characterized in that the measurement signal is associated with, in each case, one of the at least two different input or characteristic variables of the brake wear sensor, depending on different operating states of the disc brake.
For this purpose, an evaluation device can, for example, be integrated into a brake control unit or, alternatively, can be arranged separately, receiving existing brake system signals and data relating to the respective state and evaluating them in order to evaluate the measurement signals of the brake wear sensor.
A disc brake includes the brake wear sensor described above.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.